Answer: Number of molecules of hydrogen gas 
Explanation:

Number of moles of sodium =
According to reaction , 2 moles of sodium produces 1 mole of hydrogen gas , then 2.11 mol of sodium will=
of hydrogen gas that is 1.05 moles of hydrogen gas.
Number of molecules =
moles of substance
Moles of hydrogen gas formed = 1.05 moles
Number of molecules of hydrogen gas =
moles of hydrogen gas
Number of molecules of hydrogen gas 
Answer:
179.87 g/mol
Explanation:
First you need to determine the number of each elements in the molecule. This information comes from the molecular formula.
Ze(NO3)2 tells us that there is 1 Ze atom and 2 NO3 anions per molecule. each NO3 anion will have 1 nitrogen and 3 oxygens. Due to that, one molecule of Ze(NO3)2 will have 1 atom of Ze, 2 atoms of nitrogen (N), and 6 atoms of oxygen (O).
Next you need to add all of the individual atom's molar masses to get the over all molar masses. The molar masses of each element is in the question but it can also be found on the periodic table.
molar mass of Ze(NO3)2 = 55.85g/mol + (14.01g/mol*2) + (16.00g/mol*6)
molar mass of Ze(NO3)2 = 179.87 g/mol
I hope this helps.
The balanced equation for the above reaction is
2NaOH + H₂SO₄ ---> Na₂SO₄ + 2H₂O
stoichiometry of NaOH to H₂SO₄ is 2:1
number of NaOH moles required-0.5000 M / 1000 mL/L x 21.17 mL = 0.010585 mol
According to stoichiometry, acid moles required are 1/2 of the base moles reacted
Therefore number of H₂SO₄ moles reacted - 0.010585 /2 mol
Number of moles in 42.35 mL of H₂SO₄ - 0.010585 /2 mol
Therefore in 1 L solution - (0.010585) /2 / 42.35 mL x 1000 mL/L = 0.125 M
Molarity of H₂SO₄ - 0.125 M
Answer:
a single-replacement reaction replaces one element for another in a compound. A double-replacement reaction exchanges the cations, or the anions, of two ionic compounds.